-18.A diffraction grating that has a uniform distance of 4.0 x 10-4 cm between slits is being illuminated by monochromatic light (a = 6.0 x 10-2 nm) shining perpendicular to the
grating's surface. A second-order maximum will be observed at what angle from the central
maximum?
a.20°
b. 17°
c.90°
d. 0°

Yvette hangs a 2.4kg bird feeder in the middle of a rope tied between two trees. the feeder creates a tension of 480 n in each side of the the rope.

Suppose a wheel with a tire mounted on it is rotating at the constant rate of 2.15 times a second. a tack is stuck in the tire at a distance of 0.373 m from the rotation axis. noting that for every rotation the tack travels one circumference (a) find the tack's tangential speed. (b) what is the tacks radial acceleration?

Two resistors r1 and r2 may be connected either in series or parallel across an ideal battery with emf ε. we desire the rate of energy dissipation of the parallel combination to be 8.75 times that of the series combination. if r1 = 105 ω, what are the (a) smaller and (b) larger of the two values of r2 that result in that dissipation rate?